3.3 Sidecar connection to motorcycle

From Sidecarwiki

I always strive to get my mounts as far apart in both the vertical and horizontal plane as possible.

The image shows the bike mounts on my '82 GS1000G sidecar, that I no longer own.

GUIDE-LINES FOR FITTING A SIDECAR - A SERIES OF ARTICLES PULLED OFF THE WEB

While the advice contained herein is given in good faith, the Federation of Sidecar Clubs and its officers, committee members and helpers have no control over the use or application of these Guidelines and cannot be held responsible for any consequential circumstance

Having chosen the motorcycle and a suitable sidecar you have first of all to make the firm decision that all work done on the combination will be of the highest quality, particularly with respect to safety. This cannot be stressed too highly. Starting with the two components you must decide just where to put the sidecar in relation to the motorcycle. The parameters used to describe this are Lead, Lean-out and Toe-in.

Sidecar wheel lead The distance straight forward from the rear axle of the bike to the sidecar wheel spindle is known as the lead. The value can be anything from zero on some vintage outfits to as much as 50cm. As lead is increased the weight distribution improves until a point is reached where the steering becomes too heavy and tyre wear becomes excessive. A good compromise will usually be found between 15 and 35cm. It is not critical and may in any case be dictated by where the fittings can be positioned.

Motorcycle lean-out When fully laden it is important that the bike should not lean towards the sidecar; if it does the steering will be heavy particularly when turning away from the side-car. The amount of lean-out is measured at the steering head of the unladen motorcycle and is usually less than 3cm. Outfits with car tyres, particularly wide, low pro-file ones, should be set up with zero lean-out.

Sidecar wheel toe-in Toe-in is defined as the amount by which the track width at the front wheel is nar-rower than at the rear. It is measured using a pair of straight edges, one along the motorcycle wheels and one along the sidecar wheel extending forward to the front wheel. If the front and rear wheels differ in width this should be allowed for. Too much toe-in will scrub the tyres on turns toward the sidecar and let the outfit drift towards the middle of the road under neutral steering. Too little toe-in and the outfit will favour the gutter. In practice it is usually found that a well set up outfit will move slightly towards the kerb under acceleration and slightly away on braking. A typical value would be 10 to 20mm, rarely, as much as 35mm. This measurement can be critical to the steering bias of the combination and the more lead you have the less toe-in you need. Having decided where the sidecar wheel should be positioned it remains only to bolt it on and wire up the lights. Very few modern motorcycles have any provision for the fitting of a sidecar. With the increasing use of aluminium frames, square section tubing, integral fairings and the absence of lower frame tubes, it is likely that you will need the help of the sidecar manufacturer. Charnwood, Unit Sidecars, Wasp, Watsonian/Squire and West Country Sidecars all offer a fitting service and it is well worth enquiring to see if one of them has tackled the particular bike you have in mind. All fittings should be attached securely to the main frame of the motorcycle; do not use passenger footrest hangers as these are seldom strong enough. The rear subframe on some machines is only a lightweight affair to carry the saddle and should be strengthened if necessary. If a sidecar lug is incorporated, (rare after about 1965) use it; these are typically found at the steering head and top or bottom of the saddle tube. The recent fashion for "retro" bikes does provide frames with round tubing to which it is relatively easy to fit traditional clamps. In the absence of lugs try to position the fittings near cross members so that loads are transmitted to both sides of the frame and advantage can be taken of any triangulation offered by it. The usual four points for fittings are generally arranged as follows:

Top front There are broadly speaking three types of frame to be encountered; single down-tube, twin down-tube and no down-tube. Fitting to the first type should be by means of a substantial clamp as high as possible on the down-tube; this gives less chance of frame flexure and less likelihood of the fittings interfering with the front mudguard on heavy braking. Twin tubes give three possibilities; a single clamp on one tube as high as possible, a pair of clamps across both tubes sharing the load of the fitting, and thirdly, if there is a convenient cross member near the top this may be used with a single clamp. Frames lacking a front down-tube or engine cradle are very common today. Sub-frames are available for most of them as part of the fitting kit. Sometimes it is possible to pick up on the frame under the tank, or the top engine mount may be used, modified or replaced with one suitable for hanging a sidecar. In any case the sidecar manufacturer should be consulted.

Bottom front On older machines this may be a single frame clamp or the engine plates may be used or an engine bolt may be replaced with an eyebolt of appropriate dimensions. Panther and Vincent machines, being without down-tubes, used a lug directly into the crankcase. Think very carefully before doing the same on an engine not designed for it. It will be part of the sub-frame for many modern motorcycles.

Top rear This should be fitted to the main frame under the saddle nose or at the top of the rear shock absorber on a twin shock machine. Monoshock frames usually have very light rear subframes designed only as saddle supports and either additional gusseting or a special subframe will be required. If it is possible to take this fitting through the body to somewhere near the sidecar wheel this will vastly improve the rigidity of heavy or powerful outfits. Finally, remember that your pillion will want somewhere to put both feet!

Bottom rear A clamp can be fitted anywhere from under the gearbox to as far back as the pillion footrest. If gusseting and accessory mountings prevent use of a clamp a bridging plate must be made to attach to bolts on the frame, e.g. longer footrest or engine mounting bolts. The bolts can be the next size up without spoiling the appearance if more strength is required. Another possibility is to use the centre stand mounting as the stand itself is likely to be redundant. Having four good attachment points, position the bike (without stand) and sidecar next to each other, with enough space between them for your legs, using bricks, blocks, boxes etc. according to the recommended toe-in, lean-out and lead. Most sidecars look better slightly nose up (say 20mm) and of course level side to side. For most outfits it will be easier to attach the two bottom fittings first and then add the two top struts. For combinations with an old-fashioned "swan neck" this will not be possible and the top front (ie the swan neck) and rear bottom pair should be tackled first. Adjust the length of each fitting as appropriate. Next, fit all clamps, nuts and bolts but do not fully tighten them until you are sure everything is in position. It should be possible to remove any single bolt with the fingers. In other words no connection should have any stress or preload; if force is needed to take a bolt out then the plot is not correctly set up. Finally tighten all nuts and bolts so that the outfit is now a rigid unit.

IMPORTANT NO play between bike and sidecar is acceptable.

This table gives some possible solutions to different outfit performance problems. Because no outfit is the same these solutions does not work always. For sidecars at the right side of the bike you have to interchange the green text in column 2 and 3. Remember that you must adjust the settings for your cruise speed.

1 2 3 4 5 6 7 8 Outfit behavior Change Outfit pulls to the left Outfit pulls to the right Extreme sidecar tyre wear Easy lifting sidecar Extreme heavy steering Front wheel swing Easy lifting rear wheel Motorcycle lean out increase reduce reduce Sidecar wheel lead increase reduce increase increase Sidecar wheel toe-in increase reduce reduce Front fork trail reduce Tyre pressure increase increase Weight in sidecar reduce reduce increase Steering damper reduce increase Gauge reduce increase increase increase Change Outfit behavior Outfit pulls to the left Outfit pulls to the right Extreme sidecar tyre wear Easy lifting sidecar Extreme heavy steering Front wheel swing Easy lifting rear wheel

Sidecar Power Usage. solo outfit engine km/h hp hp hp 16 0.4 0.8 1.1 32 0.9 1.8 2.5 48 1.8 3.5 4.8 64 3.1 6 8.4 80 5 9.8 13.6 96 7.7 15 21 112 11.4 22.1 30.9 128 16.1 31.2 43.7 144 22.1 42.8 59.8 160 29.4 57 79.8 176 38.4 74.3 103.9

By Dave Carricker: I am not at all certain that this is a good idea but since Fuzzy asked, I will briefly lay out how I personally went about setting up my rig, Fritz, a 1974 R90/6 with Jawa (Velorex 560) sidehack. It worked for me but as has been noted every rig is different.

I had already ridden the rig and to my inexperienced butt it seemed that the rig was very heavy steering and very unstable when trying to go straight.

I had done quite a bit of reading on the old sidecar.com site and had a vague idea of what toe-in/out was supposed to accomplish as well as lean and ballast.

I am lucky enough to have a nice enclosed shop with sufficient room for the rig and working space on all sides. The floor is moderately level.

TOE-IN

(1) Prior to rolling the rig into the shop, I marked a single line on the floor with a wide permanent marker that ran perpendicular to the way the rig would be setting in the shop. This became my base line for all further work.

(2) I went to the lumber yard and bought a well seasoned treated 1x6, 12 feet long. When I got it home, I ripped it down the center so that I now had to long "sticks."

(3) I measured the width of the front and rear tire with a vernier calliper and subtracted the front width from the back. I then took this number and divided it by two. I then cut a strip of scrap lumber that width and an inch or so high. (No, Ken, I did not take the time to measure the air pressure or made any special effort to avoid the raised lettering on the side. As will be seen later it probably doesn't matter.)

(4) I stole four bricks from my wife's patio supply. I did make sure that they were all the same size.

(5) I rolled the rig into the shop until the rear end of the bike was about a foot past my perpendicular line on the floor.

(6) I laid my two long sticks on the floor side by side between the bike and the hack. I then moved them until they were both protruding about six inches beyond the line on the floor behind the bike. I then marked both sticks with the same permanent marker. I could now ensure that they sticks would always stay in the same placement in relation to my baseline.

(7) I put a brick behind the bike next to the baseline and another behind the hack, also behind the base line.

(8) I laid one stick on top of each brick and pointing toward the front of the rig. They were now roughly parallel to one another with one running along the inside of the bike tires and the other running along the outside of the hack tire.

(9) I moved to the front of the rig and placed a brick under each of the sticks near the other end.

(10) I got out my carpenter's square and using it as a guide marked the position of the axles on the two sticks. This then ensured that the bike and hack would always be placed the same in relation to the sticks and thus in relation to the base line.

(11) I took the piece of wood mentioned in step (3) and screwed it to the stick laying next to the front wheel. This then accounted for the offset difference between the front and rear tires.

(12) I then "attached" the sticks to the tires using some wood clamps.

(13) I made two final marks at the point where the two bricks were located at the front of the rig. This was an arbitrary distance but turned out to be about three feet.

(14) I was now ready to make my first measurement for toe. I used a steel tape to measure the distance from the inside edges of the sticks just above my baseline and the distance between the inside edges of the sticks at the front bricks.

(15) This initial measurement showed a difference of about 1.5 inches. I decided to reduce this number by one third and so loosened up all the pertinent mounting bolts and adjusted until the difference between the two sticks, measured at the same point was one inch.

LEAN

Had I known then what I know now, I would have adjusted the lean first. As it so happens I was fixated on toe-in like most newbies are.

(1) I attached a plumb bob to the left handle bar end and marked the point on the floor where it touched the floor.

(2) I thought about getting out my carpenter's roof triangle but decided that a degree measurement would be meaningless to me anyhow.

(3) Instead, I loosened all the pertinent mounts and tugged on the bike until the plumb bob was pointing to a new point on the floor about 1/2 inch further out than before.

THE TEST RIDE

(1) I rechecked my toe-in (it had moved a bit) and tightened everything down.

(2) I carefully removed my newly made measuring sticks and rolled the bike out and went for a ride.

(3) The result was that the steering was much lighter and the wandering feeling was much reduced.

From that point on I played with the adjustments periodically make reference marks with dates on the floor and the sticks. At one point I went with a fair amount of toe-out and actually liked the way it felt but the bike's rear tire was going away very quickly so I got rid of that right away.

As a result of paying attention to what I was making happen in the shop and the result on the road I began to develop a sense of what I was doing to the point where I seldom bother with the sticks, bricks, plumb bobs etc. I suspect that most moderately experienced sidecarist have also reached this point, particularly if they do their own set-up. I now feel confident enough to make the roadside adjustments I mentioned in my earlier post, sometimes simply to accommodate the road that I am on. It ain't electric but five minutes with two 19 mm wrenches will allow me to change the lean enough to make the super slab two lane US 400 a pleasant ride instead of a constant pull to the left that it would be if I left it set-up for county roads with their high crown and narrow width.

As a side note, I was also able to determine the "lead" by placing the two sticks side by side and measuring the distance between the rear axle mark on one stick with the sidecar axle mark on the other. Whoop T Doo! It was 17" but I still can't figure out why I should care about that one.

Another side note on ballast. All the "hot dogs" say "Rid Thou self of The Burden of Ballast". To which I say, "To hell with that, I need it to feel comfortable. If you can ride without it, power to you. I personally have installed a piece of 3/4 inch steel between the sidecar and the sidecar frame (flat and parallel to the road) that weighs about 65 pounds as well as an auto battery set-up that added another 40 pounds or so. If I were ever to take anyone of any substantial weight for a long ride (hasn't happened yet) I would drop the ballast plate.

I may have left something out but I ain't make this book any longer. Remember, someone asked for it!

Dave

SETTING UP A SIDECAR RIG Article & Photo’s by Bruce D. Stephens

There are many ways to set up and align a sidecar to a motorcycle and this is the procedure I use for my 1970 Honda CB750 with Ride-By-Side sidecar. Most of the procedures have been borrowed from others, which have been well documented over the years. This article is not going to cover all the decision making in determining track, lead, sidecar and motorcycle attachment points, etc. These subjects have been covered extensively and are documented in the Sidecar Talk 2 Knowledge Base at the Internet Sidecar Owners Klub site, www.groups.yahoo.com/group/sct . This article is more for realignment if the rig has been separated for one reason or another.

Ideally, the rig should run straight down your average crowned roads, without pulling left or right and with the rig loaded as it is run most often. In this configuration, the sidecar should be as close to level with the horizon as possible. The crown in the road and the sidecar drag on the motorcycle, wants to steer the rig to the right for a set up with the car on the right hand side. The opposite is true for a set up with the car on the left hand side. To over ride this steering to the right, the motorcycle is leaned out from vertical to the left.

Typically, highways are crowned ¼” per foot for water run off and you want to allow for this crown when setting up your rig. Since the track on my rig is about 50”, I allow for a 1” crown. I use a Pine board, 1” thick by 41/2” wide by 82” long with a centerline marked down its complete length. By placing the motorcycle on this board and aligning the tires on the centerline, you can measure off the side of the board when checking tow in and not have to bother dealing with the difference in tire and wheel sizes between the front and rear tires.

The steps to take are as follows.

1. Make your set up on as flat a floor as possible. 2. Place your board down in the set up area to allow enough working space all around the motorcycle and sidecar. 3. Push the motorcycle up on the board and align the center of the tires with the centerline you have marked on your board. Chock the front and rear tires so the bike can’t shift fore/aft. Photo’s 1 & 2. 4. Fill the tires with air to the specified amount listed on the tire for maximum load. This applies to motorcycle tires only. Some installers fill the tires five pounds over the listed maximum. You want the sidewalls stiff. My pressures are 32 pounds front, 40 pounds rear and 32 pounds sidecar. 5. It will have to be decided at this point, where in the adjustment range you want to start with adjustable rear shocks and set them to this setting. If you have a way to adjust the front fork spring settings (air pressure, etc.), set them now too. 6. Develop a method of supporting the motorcycle in the vertical position off the kick or center stand, with the flexibility to tilt it either way a few degrees. The method used to tilt the motorcycle should do so without changing the suspension settings. 7. Add weight to the motorcycle to simulate the weight of the driver, passenger, gear normally carried, etc. Position the weight on the motorcycle where it will actually be carried. Photo 3. 8. Compress and release the suspension a few times to settle in the suspension. Mark for future reference, where the front forks and rear shocks come to rest. 9. Place a magnetic protractor on the front brake rotor. Photo 4. 10. Tilt the motorcycle out from vertical one degree (as a starting point) and support it in this position. 11. Using a plumb bob or carpenter square, mark the centerline of the front and rear axles on the floor and board. Photo’s 1 & 2. 12. Draw a line on the floor, five foot long from these axle centerlines perpendicular to the board. Tow in will be measured along these lines. Photo’s 5 & 6. 13. Position the sidecar next to the motorcycle. Some people have built themselves adjustable dollies to support the sidecar frame, which allows them to move the sidecar into position easily.

Support it in this position with the frame horizontal fore/aft and side to side.  A couple of levels can be used to monitor this. Photo 7. The sidecar wheel is to be vertical and towed in. The suspension is to be loaded as it would be under most driving conditions. Photo 8.

14. Extend a tape measure out along the lines you drew on the floor, that extend out from the front and rear axle centerlines. Photo’s 9 & 10. 15. Support a straight edge about four to six inches off the floor and have it touching at two points along the sidecar tire sidewall. Photo 9. Attach two plumb bobs to the straight edge, just over each tape measure that extends out from the axle centerlines. Photo’s 11, 12 & 13. In this configuration, you can read the front and rear measurements and determine your tow in setting. I set mine to ¾” to start. 16. Attach all your struts to their mounting brackets, trying not to disturb the tow in, lean out and frame level in the process. Snug up the mounting hardware. Recheck your tow in and lean out and frame level dimensions making sure that the straight edge is still touching two points on the sidewall. If it changed, loosen up the mounting hardware and shift things back into position and retighten. You may have to do this a number of times until everything is where you want it. Once everything is where you want it, tighten all mounting hardware good and tight. Recheck your tow in, lean out and frame level again. 17. Document these starting dimensions and complete connecting anything that still needs to be connected. Wiring, sidecar body if it was removed, sidecar brake, sway bar, etc. 18. Remove all of your alignment equipment and weight that that you added to the motorcycle to simulate your weight. Roll the motorcycle off the board and prepare for a test ride. Remember that you want to have as much weight still in the sidecar as you normally carry. 19. For your test run, you want to choose different roads with different crowns to see how the rig handles on each. If you feel that the rig pulls too much left, you will have to go back and reduce the lean out. If it pulls too much to the right, you will have to go back and add more lean out. It will be trial and error until it feels right most of the time. It will never be perfect for all roads or loads you carry. 20. It is too early at this point to know if the tow in is okay. You will need to watch the tire wear before making a determination. There is good documentation on this subject in the Sidecar Talk 2 Knowledge Base. 21. Life is one big compromise and so is setting up a sidecar rig. 22. Photo’s accompanying this article can be found in the Sidecar Talk 2 Photo Gallery – http.//groups.yahoo.com/group/sidecartalk2photogallery – The photo’s are in the file titled ‘Setting Up A Sidecar Rig – By Bruce’.

MOUNTING HARDWARE

Sidecar Dynamics

Effect of Leaning R60/2 with Globe GS200 and Bathroom Scale under Sidecar Tire Leaning left: 142 lbs Sitting upright: 168 lbs Off bike: 170 lbs Leaning right: 200 lbs

From "Riding with a Sidecar" by USCA

Low speed wobble: The sidecar tries to pull the motorcycle to the right. Because of the lever action of the trail the handlebars pull to the right. The propulsive force of the motorcycle tries to straighten the handlebars. This tug of war continues until with the increase in speed, the action of the propulsive force gains the upper hand.

Also "the steering of almost every motorcycle with sidecar begins to oscillate at about 25 mph. Because of this, a steering damper is required. There are motorcycles with sidecars you cannot ride for more than 15 feet without a damper"

Factors that affect wobble: Shock stiffness Steering damper Front wheel balance Tire pressure Swingarm bushing Rigidity of sidecar mountings and fittings

Sidecar position: Moving sidecar forward will cause pulling to right Moving sidecar rearward will cause pulling to left, hard to turn right and left and excessive tire wear.

From Hal Kendall in Sidecar Talk

From: "Hal Kendall" <hal-kendall@w...> Date: Wed Jun 25, 2003 Subject: Re: [SCT] Re: Toe In and related topics

1. There is NOT any single MAGIC number that will satisfy ALL bikes, sidecars, situations,

2. The range of generally acceptable values, including whatever H-D, BMW, and any other manufacturer suggest, is a starting place. The final value is what works for you, your driving style, the typical loading, the typical roads you drive over, whether flat super slabs or highly crowned county roads. Most seem to try for between 1/4 inch and 1-1/2 inches, or the equivalent in degrees if you have a new computerized BEAR toe-in machine in your garage. Sorry, I did add one too many zeros, it was near midnight when i posted. Say from 0.2 to 0.8 degrees.

3. The easiest way to measure is to line up the center of the front and rear wheels of your rig over a single straight painted line on the flat surface of a clean double garage. This eliminates the problem of how to take the difference in width of the front and rear tires into account. Make sure the front wheel is lined up dead ahead. Take a straight plastic pipe, 4" diameter, lay this alongside the sidecar tire. Cut the pipe to the same length as you measure from just in front of the front tire of the MC to just to the rear of the rear MC tire. The pipe guarantees that you get good tire point contacts on the front section and the rear section of the sidecar tire. Otherwise, take a 4" x 2" straight board, wide side flat, sitting on a front and a rear brick, again to get the reference points off the ground. Just at the rear of the rear MC wheel, measure from the line to the outside of the pipe, call this width "A". Just at the front of the front MC wheel, measure from the line to the outside of the pipe, call this width "B". Then toein is the difference, or the value "A" - "B".

4. This is your starting point. Test drive, Change until you get the very best handling. Do not make big changes.

5. All items work in harmony. Leanout, 1 to 2 degrees, or 1/2 to 1 inch, measured from the saddle. Use the line running up the centre of the rear tire to determine angle of bike.

6. Leanout wants to make the bike want to turn to the left. Picture a solo bike leaned over to the left, it wants to go left.

7. The drag of the sidecar wheel from its weight and the friction of the SC wheel axle and the drag of the SC tire, wheel, etc tends to want to make the rig go to the right.

8. The frontal area of the sidecar, build as a box with a drag of a stone, tends to make the rig go to the right, more so at higher speed.

9. The crown of the county road tends to make the rig want to turn to the right.

10. The toein of the sidecar wheel tends to make the rig turn to the left. Too much toein and you will get excessive tire wear, especially on the rear. I have shredded the rear tire from new in 700 miles with a near empty chair. You cause the tires to scrub against each other. If you see the tread is feathered you have a badly setup rig which will eat tires.

It is your task to balance all these right and left turning forces so that your rig goes straight ahead. A poorly setup rig will wrench your shoulder out of place in a few hundred miles. A well setup rig will be a pleasure to drive. This task is more easily resolved by fitting either an adjustable lean control, and/or an adjustable toe-in control

Bottom line - no magic numbers, just a place to start. If you have a BMW, begin with their recommendation, Same for H-D.

Remember, the smaller the trail, the more twitchy the steering. Racing outfits go down to near zero. Street hacks from 1.5 to 3.5 inches. For high speed solo tourers from 3.5 to 5.5 - no magic numbers. The larger the trail the larger the self-centering force. The smaller the trail the lower the self-centering force. Self-centering force is seen when the rig wants to straighten itself after you turn into a corner. It also helps to dampen the dreaded wobbles.

Lead is mainly to minimize the bike from flipping over on sharp left-handers. Keep weight in SC to rear. Too much lead causes more scrubbing force on lefthanders. Also on righthanders except that sidecar wheel is light because of centrifugal force. No lead makes for easier steering. Again, no magic numbers. Most seem to operate from 8 to 12 inches, some have gone to 15 inches.

Rims:

 Do NOT try to install a 15 inch car tire onto a 15 inch motorcycle rim, unless you are absolutely sure you know what you are doing.   A 15 inch car tire is designed for a 14.968" rim; a 15" motorcycle tire is designed for a 15.080" rim.  Does not sound like much, but may be enough difference for a serious explosion.   If the rim is fat enough/thick enough, it may be possible to turn it on a lathe.   Maybe.  Maybe not.  BEWARE!

The above caution, AFAIK, does not apply to 16 inch and 17 inch wheels and tires. Sidecar folks sometimes use rear tires on the front of the tug, with the directional arrow, if present, reversed. This is acceptable practice, even admittedly so by such as Metzeler. It is possible to seal a tube stem via rubber washers and exterior nut to the rim to hold air better, if the tire/tube is punctured. But, that must be offset with the knowledge that if the tire rotates any on the rim, it could rip the stem out of the tube. Thus, one should understand that, in truth, for stock bikes, the tube nut is for help in installing the tube, then to be NOT used....or to be up against the valve CAP, NOT the rim. BMW makes a special all-metal valve stem that fits in original valve stem holes, but is for tubeless tire use....and it comes with the core, metal cap, nut....and rubber O-ring. part 36-32-1-452-748 a NICE part! This type of part is available at 1/3 the price, elsewhere's. Some rims are not flat on the inside, and will require spot-facing for this item. Sidecar folks sometimes do all sorts of things that are not necessarily consider OK on a solo two-wheel motorcycle.

Photos of my BMW-Ural rig. This is a 1983 BMW R100RT and a Ural hack; other views are in photogallery.htm on this site. The tug has a dual-plugged engine with raised compression ratio, the front forks are UNIT, with stock dual Brembo brakes. The rear drive is 3.36:1. The rear brake is the stock single Brembo disc brake. Front wheel size is 19 inch, rear wheel size is 18 inch. Rims are stock. I have two rear wheels, one has road rubber, the other has an Enduro tire. The sidecar tire and rim are stock Russian Ural items, 3.50 x 18. The left side of the tug has a Luftmeister 1 gallon auxiliary fuel tank. A very long list of other modifications have been made. The fairing is stock BMW "RT" type, and the lowers are still in place, although the right side one is modified for the upper strut of the sidecar attaching. The attachment to the tug is via a subframe of the Lowell Neff style, somewhat modified from his design. Even though of steel, the joints and fitments were HELIARC'd. There are two upper struts and two lower ball mounts. The subframe, photos later herein, picks up numerous points on the tug frame. There are some frame beefups on the tug, nothing major, but what WAS done was deemed important. There have been ZERO problems since this rig was put together in 2001.

The photo below is of me, at one of the Griffith Park Sidecar Rallies.

Below photo was taken January 12th, 2005, a bit over two months before a much nicer spare tire carrier was installed

BELOW is a view of the added hack brake pedal, made from a salvage yard aluminum BMW pedal. I cut off the L section from the left side of the pedal, and welded it onto the right side of the added pedal. A long piece of steel round rod was added to the sidecar brake rod angularly under the sidecar for additional strength;... the angle was to help to avoid any bending, then that rod was welded to a somewhat shortened Ural slotted lever, and then bent downwards and then extended to the left, towards the bottom in this photo. The rod then had an additional round rod welded to it, for the BMW stock brake pedal to push against. Note how the modified pedal presses only on the Ural's brake rod, but the tug's brake pedal presses on that AND its own, stock, hydraulic cylinder. Thus the two brake pedals are independent. Normal stopping is done with the tug's stock pedal, which applies a light braking to the sidecar wheel at the same time. If the other pedal is used, the sidecar braking can be done separately, and as much braking as desired, independent of the tug brake. This can be very useful for tight right turns. The mounting for the added pedal is a special shoulder bolt, to maintain a tight assembly without noticeable play. A small spring keeps the pedal from vibrating, at its tip, onto the brake rod. An adjustable stop, hard to see at the top here, sets the amount of distance the pedal is off the brake rod.

Another view of the dual pedals, and also showing the upper rear strut. The pedal on the left is the stock BMW pedal for the rear brake. Notice that actuating the BMW rear brake applies pressure onto the sidecar brake, but the sidecar brake pedal activates only the sidecar brake. The hack pedal came from a BMW junkyard, and its toeplate is a bit different, it is centered, not offset....but any version would do. Not shown is the underside of the right pedal, which I slightly modified with a common file, so that the sidecar brake will have limits. Due to the normal, stock, limited travel of the BMW pedal on the left, and careful adjustment of the Ural brake adjustment nut (on the Ural wheel brake rod), it is not possible to lock, or overly brake, the sidecar wheel, from the BMW stock pedal on the left. This worked out PERFECTLY! Thus, this setup is 100% mechanical without ANY tug rear disc brake hydraulic changes, and very reliable, for braking of the sidecar wheel. This SAME sort of thing would be easy to do on a BMW tug with drum rear brake.

This is the subframe that is on the right side of the R100RT. The upper portion at the top of this photo fits the ADDED cross piece above the stock area battery. The lower part, horizontal, attaches to the rear frame, the rear footpeg, other places, and to both engine bolts. This is a Lowell Neff design. It is exceedingly sturdy.

((NOT pictured: the upper front mount, which mounts at the BMW frame cross piece, just under the steering head)). There are TWO ways of doing that part, one is welding, one is a special sturdy clamp. I dislike welding on the BMW frame, and used a clamp....in fact I purchased mine directly from Lowell Neff. It places front strut forces directly into the existing, stock, BMW frame AND BMW STOCK CROSSPIECE.

Below are some views of the struts; steering damper setup (with several hole adjustments), front and rear lower mounts, and a rear view. The clamp and plate assembly for the steering damper was made with several holes, so it could be made adjustable for stroke and other effects. The damper is a VW type, and there is only ONE Heim joint, and the sidecar upper strut end of the damper has the stock damper's rubber mount in the 'eye'. Originally two Heim joints had been used, but I found this to have, due to the complex angles of use, too much effective movement before damping began, and thus a lot of time was spent getting just the right angles and clamping, so I could eliminate one Heim joint. There is ZERO instability, no wobbles, etc. The stock BMW hydraulic steering damper still exists, but is not powerful enough, hence the VW damper. It would be possible to set the added damper mounting plate holes further inward, for LESS stroke, and less steering effort, if the BMW damper was turned on to position 1 or 2. Dampers, whether hydraulic or friction, are always a compromise, too much damping makes for heavy handling, too little can allow the front end to oscillate badly. Each rig is different. NOTE!....The VW Beetle damping unit is used by a LOT of sidecarists. It is important that it be used correctly, or poor return of the steering to straight ahead, will be seen, and stiff steering (higher forces). For some folks, use of the Beetle, NOT Super-Beetle, damper, may be better....for some, the Super is better. The VW standard Beetle damper can be attached to some tugs by replacing an upper shock mounting bolt...with a Heim attachment. Try to avoid using two Heims in your installation, it often gives rise to excessive movement before dampening. The end of the standard Beetle damper is 10 mm, and if one can not get a 10 mm threaded Heim...sometimes hard to find....then one could consider using a 3/8" Heim, and run a 3/8-24 tap over the 10 mm end. The other end of the dampener attaches to the front strut...you can weld on a tab, or use a clamp, or whatever is really needed. In MY installation, I use the standard dampener end of 90 degrees as shown, and bolted a Heim to it, and the strut end is a bolt-on clamp (after all, the strut needs adjustability). I kept the rubber bushing in the eye of the dampener, it was needed. Originally, I'd tried two Heim's, one at each end, but this allowed excessive movement before dampening began...and, tiny as that was, it made me have to use a attachment hole on the fork clamp...see photo.....that was too far away from the fork, and whilst that gave enough dampening stroke action, it also increased the EFFORT for steering. By carefully aligning the design, I eliminated the eye end Heim, moved the attachment at the fork closer to the downtube, and that reduced stroke amount per steering amount...a NICE effect. For those that can eliminate the rubber bushing, you will be even better off.

These are special Hagon shock units, the preload is adjustable by the upper shiny collar. I found the lowest setting just fine. At the upper center area is shown some of the stock BMW oil cooler. The shocks and spiral wrapped SS brake lines all came from Heddingham (UNIT FORKS) of England. Spring and dampening of this sort of design should be such that under VIGOROUS braking, the suspension NEVER extends to rock-solid limits. If that happens, braking will be 'skipping'.

Note the damper mounting clamp-plate assembly, and the damper Heim is in the third hole from the end, that is, it is in a very close-to-fork tube position.  It gave enough dampening, without making the steering too stiff.   Use of a square front tire, the Avon Triple Duty Sidecar tire, installed AFTER this photo was taken, allowed me to move the pivot one hole inwards, for less dampening, and even easier steering effort.   The clamp(s) at the top of the Hagon units are adjustable up and down on the UNIT front ends.  This changes the TRAIL!
All that speckling is sand and gravel pitting, primarily from 7 trips to Alaska!

This shows the front Ural mount, notice the additional bolt on it! Installation was done in such a way as to INcrease the track width by about 3 inches; for easier access to valve adjustments;....see following photos about the rear mount. The rear mount is similarly beefed with an additional bolt. NOTE that the stock Ural front mount is NOT adjustable. I cut that one off, and obtained another rear type (there are at least two versions, they all can work OK here at the front), and notice the beefed up angular plate. There is a VERTICAL beef-up plate that is hardly visible just barely to the left, underside, of the two clamp bolts. This may be way overkill, but makes me comfortable!

The next two photos are of the right side of the tug, showing what I crudely did to the right side lower fairing piece. The first photo shows that I cut this piece vertically, so there is a REAR half and a front half. For the purposes of this photo, I put something (hidden) inside to move the rearmost part outward slightly, to better show the cut, in white here. By unfastening at the bottom fasteners that go to the stock metal bracket (not shown), and at the top (see second photo, inside area, where I made a simple beef-up plate), the parts are removable without having to remove the strut, bottom mount, etc.

Below is of the inside area...crudely done, but effective

This view shows the extension piece that was made up, that allowed the wheel lead to be reduced to 6 inches, a rather low amount, but one that is very easy on tires and has quick handling. The drawback is that one must be more cautious about overly-vigorous turns away from the sidecar, lest the sidecar nose go over and dig in, a very BAD thing to have happen! I do NOT recommend that most folks use 6 inches of lead on this type of rig. 9" or 10" would likely be safer for them. The photo might lead you to believe that the extension is not parallel to the hack and bike frames, but that is not so. NOTE the additional bolt on the Ural sliding mount. Note that this modification was done (and the front mount too!) such that the TRACK WIDTH of the bike-to-sidecar, was INcreased, by roughly 3 inches. That allowed for the proper access for servicing, and also I felt would make for somewhat more stable driving on common road track widths. The former more important than the latter.

This is the initial setup, with the Ural fender rack and the Ural rear rack, I am carrying a spare front tire here in this photo.

Below is a photo of the final modification of the above mount, rack, etc., completed 03/19/2005, that enabled me to carry a spare BMW snowflake rear disc wheel/tire. I can put another tire on top of the rack, or lots of luggage. In order to do this, and preserve the use of the neat looking Russian cap, the Russian welding at the bottom of the mount was ground away, and a 6 inch long metric 8.8 grade bolt, with the same end threads as the Russian cap (12 x 1.75 mm), was welded from the bottom upwards. The stock large thick Russian washer under the mount was first drilled with a large drill that was just a bit larger than the diameter of the bolt's head, this allowed the bolt head to be recessed nearly 3/4 of its head thickness. That eliminated any chance the bolt would contact the trunk lid, and added a bit of length to the bolt, which I found was needed. I then welded the bolt head to the Russian washer. A spacer was made for the wheel bearing axle opening in the wheel, so that the wheel would not move about on the long bolt, as the wheel bearing inside diameter was considerably larger than the 12 mm bolt. That spacer was made from an old piece of chrome luggage rack round tubing. A thick flat spacer, counterbored to fit the BMW internal axle spacer, which sticks up slightly from the bore, was used between the wheel's disc hub, and the underside of the Ural rack. This made for a VERY neat installation. On the Ural chrome rack on the fender of the sidecar is a 2-1/2 gallon plastic fuel container I sometimes travel with. It's weight is just where sidecar weight should be...over the wheel! I can put a much larger Jerry can there, if I wanted to. A 5 gallon Jerry can and fuel would likely weigh about 40 pounds, and be the equivalent of considerably more sidecar passenger weight, and the rig could be expected to NOT lift its wheel in right turns very easily at all. The Ural chair is a heavy one anyway. The ride, for a passenger, is very comfortable, indeed, with the stock Ural suspension system.

More photos below: The top two photos show the round solid steel spacer that transmits hack upper rear strut forces to the right side of the tug frame, and then via that added spacer, to the left side of the tug frame. This spacer is located over the battery area, using EXISTING and UNused BMW frame holes.

This is the 'crudely' modified battery tray. I'm not proud of this workmanship! Surrounding that jagged hole and not easily identified is an aluminum sheet metal piece that is inside the tool tray, it is riveted and then sealed to the inside base.

Some notes on alignment: 1. One of the very first things to decide upon when first building a rig, is the amount of wheel lead, if any. Wheel lead is the amount the sidecar wheel axle is forward, if any, of the tug's rear wheel axle. Early rigid frame tugs, such as the Harley Davidson, can use zero lead. A racing outfit might use as much as 15 inches. GENERALLY, modern bikes with modern suspensions will use 6 to 12 inches. With zero lead, there is little scrubbing on the tires on turns, but weight distribution is poor, and any tendency to nose over (rear wheel lifting on turns away from the sidecar) is worse (the rigid frame tugs are much better at avoiding this). Added weight to the front wheel is poorer for handling. If the tug weight is massive, the tendency to nose over is lessened. As the sidecar wheel lead is increased, the sidecar wheel takes more load, the weight on the front wheel is reduced. As the sidecar wheel is moved more and more forward, the more tire scrubbing will be had on turns. In fact, the sidecar wheel can REVERSE during turns if too far forward. As rear suspensions became less rigid, and the modern swinging arm was developed, sidecar lead needed to be increased. It is rather typical on a good handling and good compromise (tire scrubbing, ETC.) rig, for the sidecar axle to point to the front edge of the tug rear rim. Further forward gives better weight distribution but more tire wear, further rear eases turning effort and less scrubbing. Ideally, the lead should be as small as possible. 2. The sidecar frame should be level, as measured on a level surface. That is, the sidecar wheel side of the sidecar frame....and the sidecar frame portion towards the tug, should be LEVEL. Measure with normal weights in the sidecar and on the tug. 3. Toe-in: This needs to be checked with normal loading as with tug and sidecar, unless you find your rig will be stable with weight changes. Toe-in is needed. It will help counteract the bias and drag of the sidecar due to the wind resistance and the wheel friction and drag. Less drag means less toe-in can be used. Toe in is measured by many means, but is almost always measured off the rear wheel. Too much toe-in does NOTHING BUT INCREASE TIRE WEAR. Zero toe-in is generally a bad idea. While correct toe-in will correct for any tendency for the rig to pull towards the sidecar (not enough toe-in), that is very difficult for an amateur to figure out. If you want to try, the correct toe-in is achieved when at about 30 mph on a DEAD FLAT ROAD, when there is no tendency to pull either left or right. The HUGE problem with this is that normally the tug is leaned OUTward, to compensate for road camber/tilt, and this greatly complicates things, as does finding a truly flat road. Best, for most, to take careful measurements, set the toe to some value, and work from there, slowly, ever so slowly, making small changes in toe and lean-out, ONE thing at a time.....until things are 'sweet'. Toe-in amounts, in a big generality here, are generally about 1/4" to 1-1/2", with around 5/8" for more rigid tug rear suspensions and 1" for longer throw tug rear suspensions, as probably good values. PAGES upon PAGES could be written about how to measure, repeatedly, toe-in, by inches, by degrees, etc. I won't get into it here. Values for toe-in are usually arbitrarily measured just ahead of the front tire, and just behind the rear tire. NOTE! As lean out is increased, the sidecar wheel will tend to lift much more easily, NOT a good idea! There is controversy over lean-out. Some use Lean-In!...depends on the rig. As lean-out INcreases, it is easier for turns away from the sidecar, but the sidecar wheel can lift (fly) easier on turns towards the sidecar. Toe-in affects the amount of lean-out to be used. Too small of a toe-in will cause you to use more lean-out, with a very noticeable tendency for the sidecar wheel to come off the ground in turns towards the sidecar. 4. Still finer-yet considerations: a. To help compensate for road crown, and reduce the need for excessive leanout (sort-of), consider having the sidecar wheel side of its frame about 1/2" higher. b. Consider having the front of the sidecar frame slightly higher than the rear c. Consider having a minimum 44 inch track d. Consider that toe-in changes towards LESS, as the speed increases, due to flex in all sorts of things. e. If toe-in is too little, there may be a tendency to drift towards the gutter. f. If a rig is well set-up, it will move slightly towards the curve with acceleration, away with braking. g. Some say that about 14% lead is best (of wheelbase). h. Lean-out is supposed to be used strictly for compensating for road crown. Be sure, if using a major multi-lane highway, to drive the rig in every lane, moving over slowly, to see the crown road effects.